Conduct a series of three interrelated studies to assess the consequences of being and having an only child on intelligence, interpersonal orientation, attitudes, and time use. The research is designed to examine the consequences of growing up without siblings, particularly on the development of interpersonal skills and IQ. The research studies are grounded on the confluence model of intellectual development proposed by Zajonc and Markus which accounts for the relationship between family size and intelligence by explaining the IQ discontinuity of only children as caused by the fact that only children do not have younger siblings to tutor.